Balloons mounted on the distal ends of catheters are widely used in medical treatment. The balloon may be used to widen a vessel into which the catheter is inserted, force open a blocked vessel and/or deliver a medical device to a body location among other uses. The requirements for strength and size of the balloons vary widely depending on the balloon's intended use and the vessel size into which the catheter is inserted.
Applications such as balloon angioplasty require extremely thin walled high strength relatively inelastic balloons of predictable inflation properties. Thin walls are necessary because the balloon's wall and waist thicknesses limit the minimum diameter of the distal end of the catheter and therefore determine the limits on vessel size treatable by the method and the ease of passage of the catheter through the vascular system.
It is highly desirable for the balloon to be expandable more than once to a reproducible expanded position from an initial folded position. It is also desirable that on deflation the deflated balloon return to its initial configuration. Finally, it is desirable for the balloon and catheter to be easily maneuvered through the body lumen. These properties are determined in large measure by the cone section of the balloon as well as the flexibility of the catheter, and more particularly the catheter distal end region or tip.
There are a number of different approaches in the prior art to designing a balloon catheter having differing physical and mechanical properties in different sections of the catheter and/or balloon.
One such approach involves forming a balloon by stretching and blowing of the balloon from a segment of extruded polymer tubing. Balloons produced by stretching and blowing a tubular preform or “parison” typically have much thicker waist and cone walls than the wall thickness of their body portions. The thicker cone walls contribute to the overall thickness of the catheter, making tracking, crossing and re-crossing of lesions more difficult. Further, thick cones interfere with refolding of the balloon on deflation so that the deflated balloon can only be further inserted or withdrawn with difficulty, occasionally even damaging the blood vessel.
While there have been several solutions proposed for reducing the cone or waist thickness of catheter balloons in U.S. Pat. Nos. 4,906,241, 4,963,313, 5,304,340, 5,087,394, EP 318,919, EP 485,903, the procedures involved in these references are quite cumbersome.
Another approach involves the removal of material from the balloon cone, waist or other portion of the catheter balloon such as by chemically etching the balloon, laser ablating the balloon, etc. Such methods are described in U.S. Pat. No. 5,733,301 and U.S. application Ser. No. 09/781,388, filed Feb. 13, 2001, to Tomaschko et al. While methods of removing material are useful for a variety of reasons, they may not be particularly useful for encouraging balloon rewrapping and refolding, as well as catheter flexibility and trackability.
It is thus, a goal of the present invention to provide a balloon and/or a catheter device, and methods for producing same, that provide for various patterns and techniques for removing material from one or more regions of the catheter, including but not limited to the balloon cone, or other portion of the balloon, the catheter tip, and/or other regions of the catheter in order to encourage improved balloon refolding and rewrapping.
All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
A brief abstract of the technical disclosure in the specification is provided as well only for the purposes of complying with 37 C.F.R. 1.72. The abstract is not intended to be used for interpreting the scope of the claims.